1. Field of the Invention
This invention relates to means for resiliently fastening the railway rail to the sleeper.
2. State of the Art
Various types of resilient clips for securing the rail to the sleeper are already known and in all such constructions, the clip when fixed in position is intended to apply downward pressure on the foot of the rail, through a toe or bearing member which rests on the rail foot, and the clip includes another member which when in torsion causes the said toe member to apply downward pressure on the rail foot by taking reaction against a fixed element which is an insert also referred to as a retaining member and which is fitted to the sleeper. Each construction however has its own characteristic features in order to achieve the aforesaid objective and this will be found from some prior art constructions reference to which is given herein.
One type of resilient clip is disclosed in British Pat. No. 683,961 of 1950 which shows a construction in which the clip comprises a pair of two L-section brackets whose horizontal arms are oppositely directed to each other and rest on the sleeper. The brackets have vertical arms having openings for the passage of an actuating pin which in turn is capable of applying pressure on the clip whereby pressure is applied on the foot of the rail. The clip is made of laminated construction.
Another type of resilient clip is disclosed in British Pat. No. 706,056 of 1951. The clamp according to this Patent is in the form of a closed ring having a portion extending across the bottom flange of the rail. This portion forms one S-end of the clamp if seen in the longitudinal direction of the rail. A portion of the said clamp is then bent downwardly towards the bottom rail flange of the rail to touch the top of the said rail flange.
The clamp has opposed side portions which extend downwardly in curved form along the opposed longitudinal side faces of the sleeper and then turn back upwardly to join a portion resting on the upper face of the said sleeper. This turned back portion forms the other S-end of the clamp when viewed in the longitudinal direction of the rail. The side portions of the clamp extend at the longitudinal side faces of the sleeper beneath a pin which is inserted into a tube founded in the sleeper and projecting therethrough approximately horizontally. The clamp is, therefore, forced to slip below the projecting portion of the pin extending from the sleeper. When mounting the securing device, a vertically downwardly directed force has to be applied on the clamp for resiliently moving it down beneath the apertures of the tube so that the pin can be inserted into the tube to a position for engagement with the two portions of the clamp ring which extend along the longitudinal side faces of the sleeper to retain the clamp under spring tension. The bearing member for the sleeper consists of one or two curved portions.
There is also known another type of resilient clip called the Pandrol (Trademark) clip which is made out of a length of resilient metal of rod form which is bent so as to have, progressing from one end of the length of metal to the other, a first portion which constitutes a substantially straight leg, then a second portion in the form of a reverse bend, then a third portion extending generally in the direction of said one end, then a fourth portion which extends from the third portion, generally to that side thereof upon which said leg is disposed and constitutes a second reverse bend, and finally a fifth portion extending in the general direction towards the junction between the first and second portions, the configuration being such that when the fastening member is fitted in position, with its first portion horizontal and it is viewed in plan, the third and fifth portions appear to be on opposite sides of said first portion.